The present invention relates to apparatus for controlling temperatures of integrated circuit chips being tested on burn-in-boards in a burn-in oven or system. More particularly, the invention relates to a flow control valve that controls the flow of cooling air onto an associated heat sink for a circuit chip supported directly below the valve. The temperature of each integrated circuit chip is sensed and compared with a desired set point temperature to determine a temperature error signal and the amount of cooling air directed toward the heat sinks is varied as a function of the error signal to maintain precise temperature control.
Burn-in-ovens that are used for testing integrated circuits are well known. The prior art ovens have used various types of cooling devices for controlling the temperatures of the burn-in-boards within a selected range. Individual fans for providing cooling air directly on heat sinks, are shown in co-pending U.S. application Ser. No. 10/020,348, filed Dec. 12, 2001. The fans work well but do not provide the cooling capability of the present invention. A more passive way of controlling the heat has been to provide a flow of air from plenum chambers at the ends of an oven across a number of the chips supported on burn-in-boards and then exhausting the air out through exhaust panels.
The power required for testing has increased with the advent of circuits that consume more power in use. The ability to provide an adequate amount of cooling to each individual high power circuit under test to regulate the cooling and thus the temperature of each chip within acceptable limits has become more difficult.
The need for an easily controlled, highly responsive cooling airflow control continues to exist.